Each year in the United States, 2.5 million civilians suffer a traumatic brain injury (TBI). An estimated 5.3 million Americans are living with a TBI-related disability, costing the nation over $60 billion in annual direct and indirect medical costs. The vast majority, at least 75%, of TBIs are considered ?mild? (mTBI). After a mTBI, estimates of cognitive and other neuropsychiatric symptoms (NPS; e.g., depression, anxiety, irritability, sleep disturbances) vary greatly with estimates as low as 4-5% and as high as 49-82%. The proposed research focuses on an important, significantly understudied, population: older adults with new mTBI who account for 20% of all new mTBIs. Most recommendations for diagnosis, prognosis, and management of mTBI in older adults (here defined as >65 years) are generalized from research in younger populations. This is particularly problematic since older adults with new TBI are clinically and demographically very different from their younger counterparts. Although historically it was accepted that at all severities of TBI older individuals had worse outcomes, there is likely a subset of older individuals that have post-TBI outcomes similar to younger people. The proposed research becomes even more important when considering that the number of mTBIs in older adults continues to increase with the aging population. A recent estimate indicated that over a two-year period, 39 million older adults were evaluated for TBI (all severities) in US emergency departments (ED), a 61% increase from prior years. This pilot project will lay the groundwork for a large cohort study with the overarching goal of better understanding outcomes after mTBI in older individuals, including incidence and risk factors for cognitive decline, new onset of NPS, predictors of global and functional outcome, and associated brain imaging biomarkers. Aim 1 assesses the feasibility of recruiting a large cohort of older adults presenting to an ED after blunt head trauma and diagnosed with a new onset mTBI who are followed successfully for six months after injury to assess the above outcomes. Aim 2 assesses the feasibility of acquiring sophisticated, multimodal brain MRI in the above group within 72 hours of injury and seeks to develop preliminary imaging findings predictive of adverse cognitive and other NPS outcomes within the first six months of injury. MRI sequences to be accessed for utility are 3D morphological, susceptibility weighted, diffuse tensor, and resting state functional. By challenging the paradigm of a ?one size fits all? approach to mTBI across the lifespan, this work has the potential to impact clinical practice and assist in the identification of older individuals warranting more aggressive treatment or more thorough follow-up.